Technical Field
The present invention relates to a power supply system which is configured by individually connecting a plurality of electric storage devices to a common object to be supplied with power or a common charging apparatus.
Related Art
For example, in charging an electric storage device mounted to an electric vehicle or a plug-in hybrid vehicle, a commercial power source is connected to the electric storage device. In addition to such a usage, the electric storage device mounted such as to an electric vehicle is proposed to be used as a power-supply facility for a residential house.
Proliferation such as of electric vehicles can bring about a situation where the in-vehicle power sources of a plurality of electric vehicles are connected to a common charging apparatus, and these in-vehicle power sources are concurrently charged. Further, there can be a situation where the in-vehicle power sources of a plurality of electric vehicles are used as power-source facilities of a common electrical load, for concurrent discharge of power to the electrical load.
In a situation where the in-vehicle power sources of a plurality of electric vehicles are connected to a common charging apparatus, power supply to the individual in-vehicle power sources from the charging apparatus is required to be appropriately administered. Further, in a situation where the in-vehicle power sources of a plurality of electric vehicles are connected to a common electrical load, power supply from the individual in-vehicle power sources to the electrical load is required to be appropriately administered. For example, in a known power supply system as disclosed in JP-A-2008-236902, electric power is controlled in a situation where the in-vehicle power sources of a plurality of electric vehicles are connected to a common electrical load.
According to the technique described in JP-A-2008-236902, in discharging electric power to the electrical load from the individual in-vehicle power sources, a state of charge (SOC) of each of the in-vehicle power sources is acquired, and then an allocation of discharge power for the in-vehicle power source is determined on the basis of the mutual rate of the SOCs of the in-vehicle power sources. Determining an allocation of discharge power for each in-vehicle power source in this way can avoid a situation where any one of the in-vehicle power sources is disabled from power discharge earlier than other in-vehicle power sources. The same applies to a situation where a plurality of in-vehicle power sources are connected to a common charging apparatus and power is supplied from the charging apparatus to the individual in-vehicle power sources. In this situation, determining an allocation of charge power for each in-vehicle power source can avoid a situation where any one of the storage devices is overcharged, or fully charged earlier than other storage devices.
In setting a discharge power on the basis of SOCs, the discharge power allocated to each in-vehicle power source at the time of discharge of the in-vehicle power sources could be set exceeding the power that can be discharged by the in-vehicle power source (upper limit discharge power). In this case, in the actual discharge, the in-vehicle power source in question can discharge only the upper limit discharge power. As a result, the power supplied to the electrical load becomes lower than the requested power, arousing a concern that the performance of the electrical load becomes unstable.
In setting a charge power on the basis of SOCs, the charge power allocated to each in-vehicle power source at the time of charge of the in-vehicle power sources could be set exceeding the power that can be charged by the in-vehicle power source (upper limit charge power). In this case, in the actual charge, the in-vehicle power source in question is charged with only the upper limit charge power. As a result, there is a concern that the power supplied from the charging apparatus becomes smaller than the originally expected power.